diff --git a/http2/decoder/payload_decoders/unknown_payload_decoder_test.cc b/http2/decoder/payload_decoders/unknown_payload_decoder_test.cc
new file mode 100644
index 0000000..7ba95f7
--- /dev/null
+++ b/http2/decoder/payload_decoders/unknown_payload_decoder_test.cc
@@ -0,0 +1,100 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/third_party/quiche/src/http2/decoder/payload_decoders/unknown_payload_decoder.h"
+
+#include <stddef.h>
+
+#include <type_traits>
+
+#include "base/logging.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "net/third_party/quiche/src/http2/decoder/http2_frame_decoder_listener.h"
+#include "net/third_party/quiche/src/http2/decoder/payload_decoders/payload_decoder_base_test_util.h"
+#include "net/third_party/quiche/src/http2/http2_constants.h"
+#include "net/third_party/quiche/src/http2/http2_structures.h"
+#include "net/third_party/quiche/src/http2/platform/api/http2_string.h"
+#include "net/third_party/quiche/src/http2/test_tools/frame_parts.h"
+#include "net/third_party/quiche/src/http2/test_tools/frame_parts_collector.h"
+#include "net/third_party/quiche/src/http2/test_tools/http2_random.h"
+#include "net/third_party/quiche/src/http2/tools/random_decoder_test.h"
+
+namespace http2 {
+namespace test {
+namespace {
+Http2FrameType g_unknown_frame_type;
+}  // namespace
+
+// Provides friend access to an instance of the payload decoder, and also
+// provides info to aid in testing.
+class UnknownPayloadDecoderPeer {
+ public:
+  static Http2FrameType FrameType() { return g_unknown_frame_type; }
+
+  // Returns the mask of flags that affect the decoding of the payload (i.e.
+  // flags that that indicate the presence of certain fields or padding).
+  static constexpr uint8_t FlagsAffectingPayloadDecoding() { return 0; }
+};
+
+namespace {
+
+struct Listener : public FramePartsCollector {
+  void OnUnknownStart(const Http2FrameHeader& header) override {
+    VLOG(1) << "OnUnknownStart: " << header;
+    StartFrame(header)->OnUnknownStart(header);
+  }
+
+  void OnUnknownPayload(const char* data, size_t len) override {
+    VLOG(1) << "OnUnknownPayload: len=" << len;
+    CurrentFrame()->OnUnknownPayload(data, len);
+  }
+
+  void OnUnknownEnd() override {
+    VLOG(1) << "OnUnknownEnd";
+    EndFrame()->OnUnknownEnd();
+  }
+};
+
+constexpr bool SupportedFrameType = false;
+
+class UnknownPayloadDecoderTest
+    : public AbstractPayloadDecoderTest<UnknownPayloadDecoder,
+                                        UnknownPayloadDecoderPeer,
+                                        Listener,
+                                        SupportedFrameType>,
+      public ::testing::WithParamInterface<uint32_t> {
+ protected:
+  UnknownPayloadDecoderTest() : length_(GetParam()) {
+    VLOG(1) << "################  length_=" << length_ << "  ################";
+
+    // Each test case will choose a random frame type that isn't supported.
+    do {
+      g_unknown_frame_type = static_cast<Http2FrameType>(Random().Rand8());
+    } while (IsSupportedHttp2FrameType(g_unknown_frame_type));
+  }
+
+  const uint32_t length_;
+};
+
+INSTANTIATE_TEST_CASE_P(VariousLengths,
+                        UnknownPayloadDecoderTest,
+                        ::testing::Values(0, 1, 2, 3, 255, 256));
+
+TEST_P(UnknownPayloadDecoderTest, ValidLength) {
+  Http2String unknown_payload = Random().RandString(length_);
+  Http2FrameHeader frame_header(length_, g_unknown_frame_type, Random().Rand8(),
+                                RandStreamId());
+  set_frame_header(frame_header);
+  FrameParts expected(frame_header, unknown_payload);
+  EXPECT_TRUE(DecodePayloadAndValidateSeveralWays(unknown_payload, expected));
+  // TODO(jamessynge): Check here (and in other such tests) that the fast
+  // and slow decode counts are both non-zero. Perhaps also add some kind of
+  // test for the listener having been called. That could simply be a test
+  // that there is a single collected FrameParts instance, and that it matches
+  // expected.
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace http2